Valve for rock drills



July 21; 1931.

w. A. SMITH, JR

VALVE FOR ROCK DRILLS Filed Feb. 19. 1930 INVENTOJ-Q; 1172' wJIJmitk 174 BY M H15 ATTORNEY.

Patented July 21, 1931 warren: STATES-1 NT? OF Fl CE WILLIAM A sMrrH, 5a.,orrn1nmrsnune, new JERSEY! AssIenoR TO INGERSOLL- RAND-COMPANY, or JEBSEYCITY; NEWiJERSEY, A CORPORATION on NEW JERSEY VALVE FOR ROCK DRILLS Applicati'owfile'd-February 19, 1930. serialivo. 429,545.

This invention relates to rock drills, but more'particularly to a distributing valve for rock drills'of the flui-d actuated typ'eL The objects of the inventionare to assure 5 an abundant supply of pressure fluid to the endsof the piston chamber with a minimum lift'bf the valve, to assure a rapid and positive action of the valve, and to maintain the valve firmly seated in its'limiting positions 1e du ringthe time pressure fluid is being admitted into theipiston chamber.

Other objects will be in part obvious and in partlpointed out hereinafter.

Inthe accompanying drawings illustratl5 ing the invention and in which similar reference characters'refer to similar parts,

Figure l is a sectional elevation of so much of 'a rock 'drill'as willserve to illustrate the N invention, the valve being shown in position to admit pressure fluid into the rear: end of' the piston chamber,'and

Figure 2 is a similar- View showingthe valve 7 in position to admit: pressure fluid to p I thefront end of the piston chamber. Referring-more particularly to the drawings; A'represents' a rockdrill comprising a cylinder B in which is formed a piston chamber C to receive a reciprocatory hammer piston D. The piston chamber C is provided with an exhaust port E which is controlled by the piston D.

Any suita 1e closure may be provided for the front end of the piston chamber C. For the purpose of illustration a bushing F is shown disposed in the front end of the cylinder and said bushing has a bore G to slidably receive an extensionI-I of-the piston D.

In the rear end of the cylinder Bis an enlarged bore J for the reception of the valve mechanism which is designated generally by K and also rotation mechanism designated generally by L;

The rotation mechanism L may include the usual ratchet ring 0 which is bored to re ceive the head P of a rifle bar Q. and has introvertedteeth R to act as abutments for spring pressed pawls S of a well known type which are carried by the head P.' The rifle bar- Q, has theusual spiral flutes T to engage" the piston D in a well-- known ma-n ner for imparting a rotary movement to the piston. The arrangement is such that the pawls S will engage'the teethR and hold the rifle bar Qustationary during one stroke of the piston D. and to permit the rifle bar Q, to be rotated duringthe oppositestroke. of the piston.'=

The'valve mechanismK is disposedadjace'nt the rear end of the piston' chamber G and supports the rotation inechanism L. The rotation mechanism L therefore lies near the rear end of the bore J and in thisinst-ance the ratchet ring 0 serves as-a seat for a back head U which forms a closure forthe rear end ofthe: cylinder B.

The back head U may be secured to the cylinder B in any suitable manner andis providedwith a bore V to accommodatea rotary throttle valve TV whereby the admission of pressure fluid into the drill may be controlled.

Suehpressure fluid may be constantly introduced into a chamber X in the throttle valve and in the wall of the throttle valve is a port'Y which is adapted to register with a supply port Z in the back head U and which port opens into an annular supply reservoir b in the inner face of the back head U.

The valve mechanism K comprises a valve chest 0 consisting in this instance of a plate (Z which forms a closure for the rear end of the piston chamber C and said plate has a bore 6 through which the rifle bar- Q extends; A plate f is seated upon the plate d and like the plate d also has a bore 6 for the reception of the riflebar Q.

Disposed between the outer portions of the plates 7 and (Z is.a ring 9 which forms the outer periphery of an annular valve chamber h, and in the plate (Z is an annular recess 7' which forms a portion'of the valve chamber and opens into the inner periphery of the valve chamber 72,. Preferably a plate is is arranged upon the rear end of the plate f to form a seat for the ratchet ring 0 and for the head P of the rifle bar Q.

Disposed within the valve chamber h is a distributing valve 0 having a ring shaped portion which is adapted to reciprocate in the annular valve chamber h. On the inner periphery of the valve 0 is a lateral flange g which extends into the annular recess 7' to form therein front and rear pressure chambers r and s respectively.

The rear surface of the flange g constitutes an actuating surface 6 against which pressure fluid may act for actuating the valve and for holding it in its foremost limiting position. Similarly, the front surface of the flange q serves as an actuating surface u against which pressure fluid may intermittently act to ac tuate the valve rearwardly and to hold it in its rearmost position.

The pressure fluid utilized for actuating the valve and the piston D is conveyed to the valve chamber h by a passage '0 which extends through the ratchet ring 0 and the plate and opens into an annular supply chamber 112 in the rear end of. the plate f.

From the annular supply chamber 'w the pressure fluid flows through a supply passage x which extends through the plates f and (Z and has branch passages 7 and a leading to the rear and front ends respectively of the valve chamber h. The outlet openings of the branch passages y and a are preferably located closely adjacent the pressure chambers s and 'l and pressure fluid is admitted into the pressure chambers from the branch passages through grooves 2 and 3 formed in the inner periphery of the valve 0 adjacent the flange g and rearwardly and forwardly respectively of said flange.

'Ihe rear end of the ring shaped portion 29 of the valve 0 constitutes in this instance a holding surface at against which pressure fluid may act to assist that acting against the actuating surface 2? for holding the valve momentarily stationary in the front end of the valve chamber h. In like manner, the front end of the ring shaped portion p of the valve surface has a holding surface 5 against which pressure fluid acts to assist that acting against the actuating surface u for holding the valve stationary in the rear end of the valve chamber h.

The holding surfaces 4 and 5 are only in termittently exposed to pressure fluid and such pressure fluid is preferably that which flows to the piston chamber C for actuating the piston D. The drill is accordingly provided with a front inlet passage or passages 6 which leads from the rear end of the valve chamber h to the front end of the piston chamber C so that during the course of the pressure fluid from the valve chamber h to the front end of the piston chamber C such pressure fluid will act against the holding surface 4': to hold the valve forwardly. The pressure fluid utilized for actuating the piston D forwardly on its working stroke is conveyed into the front end of the piston chamber C by a rear inlet passage 7 which extends from the front end of the valve chamber 7b to the rear end of the piston cham ber C. The drill may be provided with a plurality of passages 6 and 7 for conveying the pressure fluid to the ends of the piston chamber but, for convenience of illustration, only one of each of these passages are shown.

In order to provide an escape for the pressure fluid acting against the actuating surfaces t and u the respective pressure chambers wherein said actuating surfaces lie are provided with exhaust passages 8 and 9 which open into the piston chamber C and are controlled by the piston D. The exhaust passage 9 leads in this instance from the pressure chamber 1" and opens into the piston chamber C at a point immediately rearwardly of the exhaust port E and the exhaust passage 8 leads from the pressure chamber 5* t0 the front end of the piston chamber G into which it opens at a point adjacent the exhaust port E.

The following is a description of the operation of the device: \Vith the valve 0 in its rearmost position, as illustrated in Figure 1, pressure fluid will flow through the passages leading from the throttle valve to the annular supply chamber, thence through the passage :22 and its branch passages y and a.

The pressure fluid flowing through the passage 2 passes over the holding surface 5 against which it acts to assist in holding the valve 0 rearwardly and flows through the inlet passage 7 into the rear end of the piston chamber C to drive the piston D forwardly. During the time the piston is moving forwardly and until slightly prior to the uncovering of the exhaust port E the exhaust passage 9 will also be covered by the piston so that the pressure fluid previously admited into the presure chamber 1" will be entrapped therein to maintain the valve 0 stationary in its rearmost position.

At the same time pressure fluid will flow from the branch passage z through the groove 2 into the pressure chamber 8 to act against the actuating surface t. Inasmuch however, that the combined areas'of the actuating surface u and the holding surface 5 exceed the area of the actuating surface If the valve will remain momentarily stationary.

As the piston D proceeds forwardly it will first uncover the exhaust passage 9 and im-' mediately thereafter the exhaust port E. The pressure fluid in the rear end of the piston chamber C will then exhaust to the atmosphere as will also that in the pressure chamber 1. The pressure fluid in the pressure chamber 8 will then act to throw the valve 0 forwardly, thus cutting off the supply of pressure fluid to the rear end of the piston chamber and establishing communication between the branch passage 3 and the front inlet passage 6.

In the new position of the valve pressure fluid flows into the front end of the piston chamber to drive the piston D rearwardly to its initial position. During the admission of pressure fluid to the front end of the piston chamber the pressure fluid Within the pressure chamber 8 will be entrapped therein by the piston D which will then overlie the exhaust passage 8 throughout a considerable portion of its stroke and the pressure fluid flowing over the holding surface 4 will also assist in holding the valve 0 forwardly.

Proceeding rear ardly the piston will uncover the exhaust passage 8 and the exhaust port E so that the pressure fluid in the front end of the piston chamber C and the pressure fluid in the pressure chamber 8 may be exhausted to the atmosphere. The valve 0 will then be shifted to its rearmost position by the pressure fluid admitted into the pressure chamber by the groove 3 during the time the valve 0 occupied its foremost position.

As may be readily observed the valve constructed in the manner described affords a Wide area over which pressure fluid flows to the inlet passages and requires only a mini mum lift of the valve. These advantages are made possible by the large diameter of the valve which this form of construction permits. Due to the small distance which the valve is required to travel it will impact only lightly against its seats and will therefore be protected against the severe jars and shocks which are usually responsible for valve breakage.

I claim:

1. In a fluid actuated rock drill, the combination of a cylinder having a. piston chamber and a reciprocatory piston in the piston chamber, an exhaust port in the cylinder, a valve chest having a valve chamber and comprising an annular recess, inlet passages leading from the valve chamber to the piston chamber, a ring valve reciprocable in the valve chamber to control the inlet passages and encircling the annular recess, a flange on the inner surface of the valve dividing the annular recess into a pair of pressure chambers, opposed actuating surfaces on the flange, grooves on the inner surfaces of the valve to convey pressure fluid directly from supply into the pressure chambers for actuating and holding the valve, holding surfaces on the valve against which pressure fluid flowing to the inlet passages acts to assist in holding the valve, and piston controlled passages leading from the pressure chambers to the piston chamber for exhausting the pressure fluid from the said pressure chambers.

2. In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a reciprocatory piston in the piston chamber, an exhaust port in the cylinder, a valve chest having an annular valve chamber and comprising an annular recess intermediate the ends of the valve chamber, inlet passages leading from the ends of the valve chamber to the piston chamber, a valve in the valve chamber encircling the annular recess and having an internal flange to divide the annular recess into a pair of pressure chambers, opposed actuating surfaces on the flange, grooves on the inner surface of the valve to intermittently convey pressure fluid from supply into the pressure chambers for actuating and holding the valve, holding surfaces on the valve against which pressure fluid flowing to the inlet passages acts to assist in holding the valve, and piston controlled passages leading from the pressure chambers to the valve chamber for exhausting pressure fluid from the said pressure chambers.

3. In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a piston in the piston chamber, an exhaust port in the cylinder, a valve chest having an annular valve chamber and comprising an annular recess opening into the inner periphery of the valve chamber, inlet passages leading from the ends of the valve chamber to the piston chamber, a valve in the valve chamber having a flange extending into the recess to form a pair of pressure chambers therein, opposed actuating surfaces on the flange, grooves in the valve to intermittently admit pressure fluid into the pressure chambers for actuating and holding the valve, holding surfaces on the ends of the valve of smaller area than the actuating surfaces and being exposed to the pressure fluid flowing to the inlet passages for holding the valve, and passages leading from the pressure chambers to the piston chamber and being controlled by the piston for exhausting pressure fluid from the pressure chambers.

In testimony whereof I have signed this specification.

WILLIAM A. SMITH, JR. 

